Spark-plug.



tions 7 and 8, the narrowest portion UNITED srnrns P Tuur orrion.

j j 'WIIIARD Gr. CAKSN, 0F RGKFOZRD, JLINOIS.

j of which the following is a specification.

This invention relates to improvements in spark plugs whereby a relatively large sparking chamber is provided, a large sparking surface isobtained therein and a clean sparking surface is maintained. Y

n the accompanying drawings, Figure 1 is a vertical sectional View showing in detail the construction of my improved spark plug. F ig. 2 is a sectional view taken approximately on line 2-2`of Fig. l, showing the insulating core and the auxiliary ground terminal. Fig. 3 is an end view of Fig. 1. Fig. 4 is a similar view of Fig. 2.

The embodiment of my invention herein snown comprises a shell 1', a metal gland 2, an insulating core 3 of porcelain or the. like, and terminals 4 and 5.v The preferably metal shell 1 is externally threaded upon one Aend at 6 whereby it may be suitably secured in the combustion end of an engine cylinder.. The opposite end of the shell is internally' threaded to receive the gland or nut 2. The central opening or passage within the shell 1 includes two reduced or o the central opening being' axially alined with the externally threaded portion 6 and the widest portion 9 carrying the internal screw threads. ri`his reduction of the central opening provides two annular ledge or shoulder portions 10 and 11.

`Within the gland and the shell and secured therebetween is. the chambered insulating core 3 carrying the terminal rods 4 and 5.. -Upon the exterior of the core and rigid therewith is a projecting annular collar or liange 12 providing two annular faces 13 and 14, the face 13 cooperating with the annular shoulder- 10, thevother face 14 cooperating with the inner end of the gland 2, said faces, shoulder, gland and shell rigidly securing the core 3 in the shell. Because of the difference in the coefficients of expan-V sion of the shell and the core., the core is preferably made slightly smaller' than the central passage in the shell and the gland. The gaskets 17 of anypreferred material, such as copper, are between the coperating facesv and surfaces for suitably sealing the Specification 0i Letters Patent.

secure the bolts in the holes.

vcured to the rod.

` Patented oct. es, 1am.

Application filed March 1, 1917. Serial No. 151,624.

joint between the core and the shell and for` preventing the core from cracking or break ing under the pressure exerted by the gland when it is threaded into the shell to rigidly secure the core therein.

Eccentrically positioned upon the end ofthe core opposite the chamber-ed portion vis a longitudinal projection 18 rigid with the core. Axially alined within said projection and extending longitudinally through the core and the projection is a hole 19 parallel to the axis of the core and adaptedto re ceivethe terminal rod 4. A second hole 20 extends through the core body parallel to the hole 19 and carries the other terminal rbd 5. The holes 19 and 20 are preferably located opposite each other, the axisofthe core being approximately midway between.

The rods 4 and 5 have enlarged end portions A 21 with frusto-conical intermediate prtioiis:

22` which are seated in the corresponding. enlarged portions 23 and 24, respectively, of the holes 19 and 20. These enlarged por. tions ofthe holes 19 and 20 communicate with the concentric annular chamber 25 in the core body. A cer'nentv packing 26 is. placed between the bolts and core body to The frustoconical surfaces 22 and 24 of the bolt and the hole cooperate to seal the. joint between the bolt and the core body. The opposite ends of the bolts are suitably secured to the core body as by the plain washers 27, the lock washers 28 and the nuts 29. 'With this construction, it will be noted that the clamp-4 ing action and the sealing action ofthe bolt head or the equivalent thereof occurs at the. widest part of the core body, thereby insuring suflicient material to prevent the core body shearing longitudinally or trans versely. From the foregoing it will be ap parent that the rod 5 may be and preferably is shorter than the rod 4 tofsecure better' insulation .between them. The longer rod 4 l have designated the current terminal and the shorter rod 5. the auxiliary ground terminal. The rod 4 carries a thumb nut 30 by which the ciurent-carrying wire which is insulated from the motor frame may be se- To the enlarged end of rod 4 is suitably secured the sparking wire 31 and to the rod 5 is similarly secured the wire 32. Each sparking wire is made of any suitable material which will not burn or fuse and comprises a securing portion 38 seated in a terminal rod, an intermediate portion 84 and a relatively long offset portion 35. The intermediate portions of the Wires convergetoward each other While the offset portions are parallel to the axis of the core body and to each other. Herein I have shown the auxiliary ground Wire 32 considerably longer than the current Wire 3l and extending beyond the shell 1. Suitably secured to the shell and preferably opposite the current Wire and in line with both Wires is the ground or base Wire 36 which has an end portion extending equally close to the auxiliary ground Wire 32 as the current Wire 31 is distant therefrom.' In this manner there will be tivo spark gaps in the sparking eircuit of equal Width and a large sparking surface between the offset portions of the Wires.

In operation it willA be 'understood that because of the large sparking surface provided a spark will always occur. Because of this large sparking surface the spark will be large and will burn any oil or carbon deposited on the sparking wires. If any earbon or oil should collect between the sparking Wires 31 and 32 and short circuit them, which is unlikely because of the large sparking chamber provided, the spark will occur between the wires 82 and 36 and at the same time the carbon or oil deposit which has short-cireuited the Wires 31 and 32 will be burned out. In this manner certainty of operation is provided, etlicient operation is assured because the sparking surfaces Will always be kept clean, and complete and instantaneous combustion is assured by the use of large sparking surfaces.

Although I have herein described in considerable detail the preferred embodiment of my invention, I would have it understood that I do not intend to be thereby limited, but will be limited only by the scope of the appended claims.

I claim as my invention:

l. A spark plug having, in combination', a shell having an elongated passage with a reduced portion providing an annular shoulder, a core comprising a body portion having a chamber at one end axially alined with said passage, a collar portion between the ends of said body portion and rigidly secured thereto providing'- a pair of annular faces, one of said faces cooperating with said shoulder, and an cecentrically positioned projection extending longitudinally from the body portion and opposite the chambored portion having a hole axiallyalined with said projection and extending through the core, the core having a second hole extending therethrougl'i and parallel to said first mentioned hole, said holes connnuncating with the chamber, a terminal rod in each of said holes, the rod ir. said first nientioned hole being the current terminal and longer than the auxiliary ground terminal .rod in the other hole, eaeli of said rods having at one end an enlarged portion and a frusto-conical intermediate portion adapted to be seated upon a complementary conical surface in each hole, said contacting conical surfaces lying approximately in the same plane as said collar portion, means upon the other end of said terminal rods for rigidly securing them in said holes, a sparking Wire carried by each of said rods having an intermediate converging portion and an elongated parallel portion Within said chambered portion and said passage providing a large sparking surface therein, a ground terminal Wire carried by said shell extending proximately to said auxiliary ground wire, and a gland nut, the inner end thereof eoperating With the-other of said faces to rigidly secure said core in said shell.

2. A spark plug having, in combination, a shell, a chambered insulating core having an eeeentrieally positioned projection eX- tending longitudinally therefrom and opposite the chambered portion having a hole axially alined With said projection and extending through the core, the core having a second hole extending therethrough and parallel to said first mentioned hole, a terminal rod in each of said holes, the rod in said first mentioned hole being the live eurrent terminal and longer than the insulated auxiliary ground terminal rod in the other hole, means for securingT said rods in their respective holes, a sparking Wire carried by each of said rods having an intermediate converging portion and an elongated parallel portion Within said chambered portion providing a large sparking surface therein, a ground terminal Wire 'carried by said shell extending proximately to' said auxiliary ground Wire, and a gland nut for rigidly securing said core Within said shell.

3. A spark plug comprising, in combination, a shell having a reduced interior providing an annular shoulder, a chambered insulating core having a collar portion betweenthe ends thereof providing a pair of annular faces, one of said faces coperating with said shoulder, a terminal rod having an enlarged end portion and a frusto-conical intermediate portion and adapted to be seated in a hole extending ,longitudinally through the core, said hole having surfaces complementary to said enlarged and conical rod portions and being approximately in the saine plane as said collar portion, means for securing said rod in said core, and a gland, the inner end thereof cooperating with the other of said faces to rigidly secure said core in said shell.

4. A spark plug comprising, in combination, a shell, a chambered insulating core, a securing gland, a plurality of sparking termin-als carried by said core and insulated from each other within the core, said terminais comprising* a rod and a Wire having; o body portion seated in said rod, an int-ennediane portion and an offset poiton, said intermecia-te portions being inciosef Within the core chamber and converging towmfd oooh other and the exis ofsaid shell and said oset portions of seid wires extending @Mooi pmafiiei to each other mici the axis of said she, and a gi'ound terminal sparking Wire Carried by said shell extending proximaeiy to one of said Wires.

in testimony whereof, have heiemu'o set my hand.

@VILLARD G. JA'KSON. 

